Stepper Motor FAQ

What does a stepper motor system consist of?

A stepper motor system typically consists of:

  • Controller: capable of generating step pulses and direction signals for the driver
  • Driver: converts the controller command signals into power to energize the motor windings
  • Stepper Motor: electromagnetic device that converts digital pulses into mechanical shaft rotation

The three types of Step Motors:

  1. Variable Reluctance:  Has teeth on the rotor and stator but no rotor permanent magnet.
  2. Permanent Magnet:  Has a permanent magnet for a rotor but no soft iron rotor teeth. Permanent magnet step motors can be subdivided into 'tin-can or can-stack' and 'hybrid', tin-can (can-stack) being an inexpensive version, and hybrid versions constructed with higher quality bearings, smaller step angle and higher power density.
  3. Hybrid Synchronous:  Combines the magnet from the permanent magnet motor and the rotor and stator teeth from the variable reluctance motor.

Are stepper motors AC or DC?

Stepper motors are generally considered to be asynchronous (AC) motors. While stepper motors are largely the same as brushless DC motors (BLDC motors), they differ in their intended use. Stepper motors operate in steps whereas a BLDC motor provides smooth motion.

  • 0.9° = 400 steps/rev
  • 1.8° = 200 steps/rev
  • 7.5° = 48 steps/rev
  • 15° = 24 steps/rev

Steps / Revolution Explained

Steps per revolution equals 360° divided by step angle (0.9°, 1.8°, 3.75°, 7.5° and 15°) when the motors are driven in full-step excitation mode.

  • 0.9° = 400 steps/rev
  • 1.8° = 200 steps/rev
  • 7.5° = 48 steps/rev
  • 15° = 24 steps/rev

Rotary or Linear Step Motors?

Step motors can be linear or rotary. Electromate® offers a full line of low-cost short-delivery hybrid rotary step motors from sizes NEMA 8 to NEMA 42, including IP65 rated step motors and stepper gearmotors. Electromate®'s step motors are available in 4, 6 & 8 lead configurations for bipolar or unipolar operation, and can be wired in series or parallel. All our step motors have optional rear shaft extensions, encoders and gearboxes.

Linear Step Motors are also known as Step Motor Linear Actuators, and have a threaded rod/acme screw in place of a smooth shaft. Linear step motors provide a simple motion system at a fraction of the cost of conventional rotary stepper motors and traditional linear motion systems. Linear step motors offers a wide range of customizable options, including various screw pitches, screw lengths, bipolar or unipolar windings, and several operating voltages.